Left to right, oldest to newest. I've since given myself a few subtle highlights, but it is not very different from that. The white balance and lightning conditions in these photos vary. It is more of an orange than a red. I think the last despite the artificial light is quite accurate
So yes, I went the DIY route... I am glad I did. Right now I am using a combination of straight bleach (very sparingly and carefully... but to lighten you have to bleach!), "professional" dyes with developer, and box dye (the dyes are rather similar and actually all l'Oreal, I am very happy with their red performance - the "pro" ones have this "Rubilane" thing - my guess is the box dye also does).
I mostly box dye on the roots since it is easy and works for me, and I use just half a package for the roots. I don't touch the lengths much in fact.
I've discovered that my hair grows pretty fast (roots every 2 to 3 weeks, which varies), so the lack of growth must be breakage. Not surprising. The dye doesn't actually have much of an effect on this (I mean it breaks anyway) so I may as well have fun. I've so far only had positive reactions. And I do like it which is what matters most.
It is not what I had in mind, exactly, but I guess it will do for now. I may still darken my roots as I originally intended, which would make for much less maintenance (it does not bother me yet, though!).